Blender and Unity. Materials/Shaders question (Cycles, BlenderRender, Does it matter??)
Check out Poliigon for amazing textures if you don't want to tinker the settings manually.    

In Blender, we mostly use Cycles Render engine and starting 2.80, the internal render engine(Blender Render) has been removed.

In order to tinker with the material settings, you need to make sure the render engine is set to Cycles render and select Node editor from the bottom left corner(change from 3d view to Node editor or extend a new tab and change it).

It works similar to how 3d View works, shift + a to add a new shader,x to delete, g to move etc..